I had a look and the source cited for it being the most efficent self-powered means of transportation is from March 1973; I wonder if there's been any new developments since then.
Random things off the top of my head: Some time ago they built a self-propelled helicopter, which also used bike technology (gears etc). I vaguely recall that people did state that rowing is what you should use to get the most energy out of a human body - it is (or can be) a full-body motion, including the large muscles in the back and legs and the smaller ones in the arms, while cycling mainly uses the legs. But the mechanism to translate rowing energy into the propellers was too heavy, or something like that.
Actually it might have been a HN thread. Here's one from 10 years ago, and it just so happens that I had made my account by then so this was probably it: https://news.ycombinator.com/item?id=6028326
I read somewhere (lost to the fickle beasts of memory and time, of course) that rowing and the like is not particularly effective, precisely because it requires big, slow movements against resistance, which the human body is not that efficient at[1]. What we are efficient at is quick, light, repetitive movements – like pedaling with the proper gear selected. This is why Ivan Illich phrased it as the bicycle being "the perfect transducer to match man's metabolic energy to the impedance of locomotion".
[1]: This is also why rowing and weightlifting are such a good type of exercise to get stronger, and why bicycling requires that you put in a lot of hours to get stronger from it.
> I vaguely recall that people did state that rowing is what you should use to get the most energy out of a human body
The limit for athletes is normally cardiovascular, commonly oxygen - VO2max the the measurement there. For less fit people it can be the cardio side, their heart just isn't up to it so their muscles fail and they lie on the ground twitching. Oxygen-deprived people pant and gasp.
So recruiting more muscle groups really doesn't help. What does is increasing oxygen intake, and this is where recumbent bikes come in. The laid back position opens the thorax and increases effective lung capacity. As well as reducing air resistance, except that that's a very subtle thing that mostly depends on the rules governing the sport in question (fairing on bike and kayak, for example, are variously restricted or banned in most relevant sports).
You can also reverse that and exercise at high altitude... less oxygen for everyone!
> So recruiting more muscle groups really doesn't help. What does is increasing oxygen intake, and this is where recumbent bikes come in. The laid back position opens the thorax and increases effective lung capacity. As well as reducing air resistance, except that that's a very subtle thing that mostly depends on the rules governing the sport in question (fairing on bike and kayak, for example, are variously restricted or banned in most relevant sports).
Recumbent riders generally have much lower peak power and ftp but higher sustained so VO2 differences wouldn't explain it. The main attribution I've seen is aero and marginally less muscle power used for motions that aren't related to pedalling.
My limited experience is that it's easier to recruit more muscles on an upright, so your peak power can be higher. In my 30's I would hit double for a 30s trial on an upright vs a recumbent (last time I had a decent power meter was in my 30's). But over 5 minutes the recumbent was better even if both were fixed to stands. So I don't think it's the balance issue.
For an hour or more the recumbent wins just for comfort, and unfaired records it wins on air resistance (that's why the UCI banned them, it let povo scum beat gentlemen athletes). But then the UCI doesn't have faired records... it's only the IHPVA et al that make that distinction.
Interestingly the PBP etc records (we don't have records, this isn't a race!) are all uprights AFAIK. But that's xenophobia rather than technical skill from what I know. And the Round Australia record is an upright, largely because no-one on a recumbent has been inclined to attempt it. RAAM is held by a bent (https://en.wikipedia.org/wiki/Race_Across_America#Records).
Recumbents are notoriously difficult to ride as the grades get steeper. Upright cyclists have the advantage using different body positions (i.e. standing), but 'bent cyclists can't do that. On the steepest grades, it can be a challenge to even keep a 'bent's front wheel on the ground.
If we take distance passed as a measurement, intuition tells me that bicycle is more efficient, since it doesn't have to lift the whole body, just move it around on wheels which provide very small friction.
Perhaps if we had bicycles with comfortable seats we can recline in, we could save up energy needed to balance our body on a bicycle. Something like a pedal boat, but with wheels.
Recumbent bikes definitely are more efficient due to aerodynamics if nothing else. I suspect being able to push back against the seat helps too, though.
This is true - the ergonomics as well as the aerodynamics are a step up. I would like to note though a disadvantage in ergonomics when it comes to hills, which nicely illustrates another feature - often unacknowledged - of conventional frames.
I live on a hill and commute on a conventional/non-recumbent bike. There used to be a bearded white middle-aged guy living half way up our hill with a recumbent and I noticed the recumbent seemed way /less/ efficient on our hill climb. A secondary design feature for conventional bike geometry is how well it works on a hill when you stand up. There’s something about how you can use your weight, pulling on the handle bars at the same time as rocking the bike frame side to side, to maximise downforce on the pedals, that just works incredibly well for propelling yourself and the bike up a hill. None of that is available on the recumbent designs I’ve seen, and because the hill slows everything down, they get less aerodynamic advantage too. So while they’re great on the flat, I think a key limiting factor for recumbents may be that they’re not so good in hilly places.
Ran into a fellow touring once with a recumbent and a trailer for his dog! All told, a 250lbs rig, few would be able to celebrate as much getting to the top of santiam pass in oregon (approx 4000 ft climb)!
I've seen a few of them in the city. The seem great, but I wonder how well they steer. They're low to the ground and seem less visible (I've seen them with flags). On a bike your center of gravity isn't much higher than walking, and you can put your feet out quickly and essentially be in a standing position .
They steer well enough for bike trails. Longer (e.g. tandem) ones may have some challenges with tighter turns (need to do a 90° adjustment at a light).
Flags are common for recumbent for visibility.
The lower center of gravity and the "it's real hard to fall off" can make it useful for people that have difficulty with balance. The back seat of a tandem is suitable for someone with needs for additional assistance ( https://www.terratrike.com/product-category/accessories/assi... ) - my mother would go tandem with one of her friends who was legally blind and needed to use a walker.
I bike A LOT -- >1,000 a month on a 29" full suspension e-bike (Orbea Rise)
But I have been biking daily for morethan a decade, and was a daily bike commuter in the bay area for ~15 years....
I see many recumbent bike a day when on the trail. At least >5 a day.
My house backs up to the American River trail, I literally leave my house and get directly onto the trail in less than 2 mintues.
Recumbents are all over the ART in the Sacramento Area.
One thing I have noticed though, and this is just a statistical observation on my part biking that trail regularly for ~2 years...
The average Recumbentist is a White Male, Typically with a beard >50 years old, 30% are overweigth, 30% are average build, 30% look semi/more-fit, 10% are female.
They look fun though. I'd love a long distance camping -e-bike version of one with a trailer and a detachable, light, curved windscreen that can be put on the top of the trailer when one wants.
> The average Recumbentist is a White Male, Typically with a beard >50 years old, 30% are overweigth, 30% are average build, 30% look semi/more-fit, 10% are female.
Recumbents also used to be far more expensive than standard bicycles (although now there's a lot of expensive standard bicycles) so an older demographic isn't surprising.
Recumbents are also lower in height and a lot easier on people's joints so are particularly good for people who have medical issues or mobility impairments. So, again, your demographics aren't surprising.
> They look fun though. I'd love a long distance camping -e-bike version of one with a trailer and a detachable, light, curved windscreen that can be put on the top of the trailer when one wants.
> The average Recumbentist is a White Male, Typically with a beard >50 years old, 30% are overweigth, 30% are average build, 30% look semi/more-fit, 10% are female.
I'm white, male, beardless, and 40 and am almost always the youngest when showing up at a recumbent meetup.
A lot of the current crop of recumbent riders (in the US at least) got into it in the late 90s and early 2000s. As the boomer cohort aged out of riding two wheeled recumbents there was a significant drop in demand for recumbent bicycles and a corresponding increase in recumbent tricycle demand. The companies making fast/racing recumbents stopped due to lack of demand (basically just Performer and Bacchetta are left) so there aren't a lot of us left in the fast recumbent bicycle crowd and almost everybody is running a 10+ year old bicycle. I have a 2009 Optima Baron, for example. More casual recumbent bicycles like LWBs or crank forwards are still around and seem to be more popular in the midwest than on the coasts. I live in NYC and recumbents are particularly rare here due to the downsides of recumbents in the city, mostly sight lines in traffic. I've seen 6 in the wild in the last 8 years and I usually see 4 or 5 recumbent trikes on mass rides like the 5 Boro but all the trikes have been from out of town.
The main losses are drag and, at low speeds, friction.
A velomobile (enclosed bicycle or tricycle where you lie back) mostly solves the former. The effort of a light walk moves you at about 30km/h on the flat (but slightly slower than walking on a steep uphill).
Steel rails would make it slightly more efficient again.
As I understand it, reducing unsprung weight (which is not very much for a bicycle with no suspension beyond the tires) can have an outsized effect, but actually reducing weight mostly matters for ascending. For non-competitive cycling, other factors seem like they should be much more significant.
A big one, which is banned in most competitive formats, is a fairing. This is much more effective than having a human hunker down and try to be aerodynamic. Even for an upright cargo bike (which is generally extremely heavy), a fairing in front can make a dramatic difference on level ground with no wind.
Which is great if one is racing but not so much for long distance riding or riding for the joy of it. Most riders are not racing at any level where it makes a difference. A well made steel frame is a joy to ride. They are incredibly comfortable and track exceptionally well, unlike stiff frames.
carbon fiber is a lot less efficient regarding manufacturing though, compared to aluminum. The difference is even bigger with respect to steel or the life time of the materials
Random things off the top of my head: Some time ago they built a self-propelled helicopter, which also used bike technology (gears etc). I vaguely recall that people did state that rowing is what you should use to get the most energy out of a human body - it is (or can be) a full-body motion, including the large muscles in the back and legs and the smaller ones in the arms, while cycling mainly uses the legs. But the mechanism to translate rowing energy into the propellers was too heavy, or something like that.
Actually it might have been a HN thread. Here's one from 10 years ago, and it just so happens that I had made my account by then so this was probably it: https://news.ycombinator.com/item?id=6028326